Questions

1. Explain the physical basis for assuming a “nuclear winter” to occur as a consequence of a nuclear war!

2. What is the KT boundary?

3. List observational evidence for the “nuclear winter” model!

The New Fear: Terrorists!

Since 911 fear of terror attacks dominates the discussion. The fear of nuclear terror through small or medium sized “nuclear bombs” from former Soviet arsenals and fear of “dirty bombs” makes headline news in the media channels.

Terror as a WeaponTerrorism is the … deliberate targeting of Civilians in order to undermine their support for the politics of their political leaders” (Caleb Carr 2002)

Deliberate use by military forces

o Roman Army: 1st to 3rd century o Mongol Armies: 13th to15th century

o German Navy: unrestricted submarine warfare in WW1o Japanese Army: Manchuria, China, Philippines, …o Spanish Army: Civil War in Spaino German Armies: occupation policies in WWIIo British Air Force: Bomb War against cities in WW2o US Air Force: Bomb War against civilian targets Germany & Japan in WW2,

Hiroshima & Nagasaki Vietnam

o Israeli Army: Palestine populationo Yugoslav Army: Muslims, Croats, Albanianso Indonesian Army: East Timor

And many examples more ….

GuerillaGuerilla: civilian fighters against occupying forces:o Spanish Guerilla (little war) against Napoleonic troopso Russian partisans against German Armieso Polish and Jugoslavian partisans against German Armieso French Resistance against German Occupationo Kuomintang & Red Army against Japanese Occupation

o American Revolution against British Ruleo Boers against British take-over of Transvaal o Mau-Mau Uprising against British Colonial Rule in Kenyao Vietminh against French Colonial Forces in Vietnamo Front de Libération Nationale – FLN fighters against

French Colonial Forces in Algeriao Vietcong against US occupation in South Vietnamo Sunni Iraqi against US occupation in Iraqo East Timor against Indonesian occupation

Strictly against military occupation forces and collaborators

Against occupation and colonial forces including civilians (settlers, farmers)

Second category often depicted as terrorist acts against legal government institutions!

Terrorist Movements

o Assassins in 9th-13th century middle easto Anarchist terror in 19th century Europeo Ku Klux Clan in the US o IRA in Ireland and Great Britaino Irgun Zvai Leumi & Lehi movement in Israelo Al Fatah in Israel, Jordan, Palestine o Red Army Fraction in Germanyo Red Brigades in Italy o Euskadi Ta Askatsuna in Spaino Shining Path in Peruo Zapatista movement in Mexico/USo Oklahoma City bombingo Unibomber (Ted Kaczynski)o Right to life movementso Islamic Al Qaeda

Terrorist actions target mainly civilian population and structures avoiding military & government installations

Timothy McVeighOsama bin Laden

The old Man of the Mountain

Present and future

generations

Awareness in US populationConfusion in US about differences between guerilla & terrorist!Ignorance and confusion also about geographical location, historic reason,historic, economic, and sociological background of terrorist attacks.

“Terrorists” Attacks

Conventional weapon based attack more likely;But a successful nuclear attack would provide high visibility and ensure long term impact.

Logistical problems include:Generating nuclear material (235U, 239Pu); huge industrial effort requires breeder reactor and diffusion or centrifugal based separation facilities (~10-20 years), requires hosting state resources

Provision of nuclear bomb material (235U, 239Pu);only possible from stockpiles of exiting nuclearpowers (Israel, Pakistan, North Korea) or leftover supplies from former nuclear powers (Kazakhstan, Uzbekistan, Ukraine). This is not inconceivable!

"one man's terrorist is another man's freedom fighter".

Smaller scale destruction by transportable nuclear device

Preferred Target - High Visibility Object

e.g. White House

Effective Range For Thermal Energy1 kT Weapon

Effective Range For Thermal Energy1 kT Weapon

Radiation effects would be limited to 10-20 km circle

Classical version seeks to enhance the production of long-termradioactivity by adding “seed material” for neutron capture, e.g. 59Co(n,)60Co – cobalt bomb.

The theorized cobalt bomb is, on the contrary, a radioactively "dirty" bomb having a cobalt tamper. Instead of generating additional explosive force from fission of the uranium, the cobalt is transmuted into 60Co, which has a half-life of 5.26 y and produces energetic (and thus penetrating) rays. The half-life of 60Co is just long enough so that airborne particles will settle and coat the earth's surface before significant decay has occurred, thus making it impractical to hide in shelters.

The New “Radiological” Version

To contaminate an area of 10,000m2 (circle of ~60 m radius) with ~1 Ci/m2

(<1 rad dose for by-passer) from material transported in a regular suitcaseyou need an initial source of ~10.000 Ci radioactive material in your explosivedevice. If the material is 60Co this activity corresponds to ~90g of pure 60Co.The dose rate is ~20 rad/s (depending how the carrier would hold thesuitcase). For 1 h hike from terrorist headquarter to e.g. Times Square in NewYork the carrier would receive a lethal dose of 72000 rad. Major Pb shieldingrequired for 1.076 and 1.33 MeV radiation from 60Co radioactive decay.(A regular laboratory 60Co source has an activity of <10-5 Ci.) An “effective”dirty bomb provides substantial logistical problems on the delivery side!

The radiological dirty bomb would contain a small or mediumamount of explosives (10 to 50 pounds [4.5 - 23 kg] of TNT,for example) with a small amount of low-level radioactivematerial (say a sample of 137Cs or 60Co from a university labor more likely from a hospital radiology department).

Identification of possible sources for larger amounts of radioactive materialCategorization of danger in terms of Activity/Dangerous activity A/Dactivity: D

radionuclide TBq Ci60Co 0.03 0.8

137Cs 0.10 3.0192Ir 0.08 2.0241Am 0.06 2.0

IAEA category ofDangerous Activity

Highest risk is in “unprotected” medical facilities

A/D > 1 isdangerous

Medical Sources

Theletherapy unitsMore than 10,000 medical sources of 60Co (T1/2≈5y), ~100 TBq ≈ 3000Ci each.Each capsule contains 10,000 pellets with each pellet 100 GBq

Third world countries prefer the less expensive 137Cs sources (T1/2≈30y) which comes as highly dispersible CsCl salt. Each unit contains ~100 TBq ≈ 3000Ci.

Brachytherapy unitsBrachytherapy sources are more abundant but have lower individual radioactivity: 226Ra, 137Cs, and 192Ir, with typical activity levels of 0.1-1.0GBq

Sources are mainly designed for the radiation treatment of cancer patients

Example for careless handling: Goiania, Brazil

A radiotherapy unit had been abandoned in aclinic which was being demolished. The unithad a source consisted of 1,375 Curies ofcesium-137 in the form of cesium chloridesalt, sealed within two nested stainless steelcontainers to form a 5-cm diameter capsule.Two individuals dismantled the unit andextracted the source. Both began vomiting onthe 13. September. The unit material wassold to a junkyard, a blue glow from thesource container was observed that night; anumber of people came to view the capsule.On the 21. of September the source materialwas removed and distributed among severalpeople, some of whom spread it on their skin.Around the 23. of September severaljunkyard employees were exposed whilefurther dismantling parts of the unit. …

Dirty Bomb Scenario #1 (~2500 Ci)

Dirty Bomb Scenario #2 (~2500 Ci)

Requirements for being prepared for possible Al Qaeda dirty bomb threats

Identification and localization for highactivity radioactive sources (IAEA)

Risk and threat assessment studies(IAEA + national agencies)

Enhanced security requirements for high activity source storage againsttheft

Enhanced security for international transport of radioactive material

International legal agreements training of radiation control personal

Signature identification, Detector array developmentSensitivity analysis

Modern X-ray or neutron scanning technologies rely on imaging techniques

Airport security - neutron activation techniques for plastic explosive search

14N+n (thermal) 15N* 15N+ (10.8 MeV)

77

+ 78

+

10.8 MeV14N(n,)15N

prompt reaction

Monitoring Radioactivity

Efficiency of 10-4 limits the detection to activities in the milli-Curie range

Problem with on-line radioactivity monitoring device is the number of false alarms due to natural activities and medical activities (patients after treatment)

Shortcomings and Limitations

Naturally occurring background from industry products

New medical related background

Number of radiation based medical diagnostics and treatment procedures have multiplied over the last decade, due to number of applications and intensity of radiation level, which raises the overal exposure